The present invention relates to a piping structure for joining tubes or pipes or the like in a vehicle by using a female connector and particularly to a piping structure without relative turning movement of a female connector and a pipe which are not bound by each other.
A variety of female connectors have been provided for joining tubes or pipes or the like in a vehicle. Such a female connector is generally made of a synthetic resin or metallic material which fixedly joins at one end to a resin tube or the like and in the form of a retainer at the other end to a corresponding pipe or the like as a male member, hence coupling between the resin tube and the corresponding pipe.
One of such conventional female connectors is illustrated as a quick connector in FIG. 7. The female connector denoted by 10 comprises a first connecting end portion 1 at one end for joining to the resin tube and a second connecting end portion 6 at the other end for engagement with the corresponding pipe 11 to be joined as having a retainer 2 therein. The retainer 2 may be arranged of substantially a tubular shape which becomes gradually greater in the diameter from one end to the other end. The retainer 2 is also elastically deformable by having at least one axially extending slit. Accordingly, as the retainer 2 is inserted into the female connector 10, its diameter becomes smaller until a pair of detents 2a provided on the outer surface engages with and snaps in windows 3a or concave portion provided in a housing 2 of the female connector 10.
When the insertion end 11a of the corresponding pipe 11 is inserted into the opening of the second connecting end portion 6 of the female connector 10 extending straight, an annular projection 11b provided on the outer surface of the insertion end 11a engages with a small diameter recess 2b at one end of the retainer 2 so that the insertion end 11a is concentrically and turnably joined along the axis L with the second connecting end portion 6 of the female connector 10 to prevent the corresponding pipe 11 from moving in axial direction. The retainer 2 has a pair of operating arms 4 provided integrally on the other end thereof. When the operating arms 4 are pressed inwardly In diameter direction to reduce the diameter, the retainer 2 with the corresponding pipe 11 can be removed from the female connector 10. Also, the female connector 10 has an annular sealing member 5 such as an O ring mounted to the inner wall of the housing 3 of a central region thereof.
In the piping structure having such a female connector 10, a resin tube (not shown) is irrotatably fixedly inserted onto the outer periphery of the first connecting end portion 1 of the female connector 10 while the corresponding pipe 11 joined to the second connecting end portion 6 of other end may turn about the axis L of the second connecting end portion 6 the female connector 10. Accordingly, any engine vibration of the vehicle or an unexpected vibration or small displacement or the like at the side of the resin tube or the corresponding pipe 11 may cause the female connector 10 and the corresponding pipe 11 to be turned relative to each other. When the female connector 10 and the corresponding pipe 11 are turned relative to each other, the annular sealing member 5 contacting between them will be rubbed and worn out thus, its sealing effect will be declined.
A means for inhibiting the turning movement of the female connector and the corresponding pipe relative to each other is disclosed, for example, in Japanese Patent Laid-open Publication (Heisei)9-269008 in the form of a piping structure where the female connector has two opposite flat regions provided on the outer surface thereof for inhibiting the turning movement. As shown in FIG. 6, the piping structure has a connector holder 12 later connected to the female connector 10 which has joined between a resin tube 9 and a corresponding pipe 11. While an arm 14 of the connector holder 12 snaps on the small-diameter region 10b of the female connector 10, a pair of opposite strips 13 of the connector holder 12 holds the two flat regions 10a of the female connector 10. Also, the corresponding pipe 11 is bent and held in a notch 15a provided in a flat body 15 of the connector holder 12 so that it can be inhibited from turning.
According to the conventional piping structure, as long as the corresponding pipe 11 is bent above the extension of the female connector 10, the corresponding pipe 11 can thus be inhibited from being turned relative to the female connector 10. It is however mandatory for the female connector 10 held by the connector holder 12 to have the small-diameter region 10b and the paired opposite flat sides 10a on the outer peripheral. Accordingly, the female connector of at least a round tubular shape is not permitted.